PointerPredictor 類別

定義

命名空間:

Microsoft.UI.Input

提供產生 PointerPoint 物件的集合的支援，這些物件可預測目前輸入 指標最可能的路徑。

public ref class PointerPredictor sealed : IClosable

/// [Windows.Foundation.Metadata.ContractVersion(Microsoft.Foundation.WindowsAppSDKContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
class PointerPredictor final : IClosable

[Windows.Foundation.Metadata.ContractVersion(typeof(Microsoft.Foundation.WindowsAppSDKContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
public sealed class PointerPredictor : System.IDisposable

Public NotInheritable Class PointerPredictor
Implements IDisposable

繼承

Object Platform::Object IInspectable PointerPredictor

屬性

ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

實作

IClosable IDisposable

範例

在下列範例中，我們會示範如何在背景執行緒上接收 SwapChainPanel 的輸入，以取用 PointerPredictor 物件。

class PointerPredictionRenderer : IDisposable
{
    private DispatcherQueueController _queuecontroller;
    private InputPointerSource _inputPointerSource;
    private PointerPredictor _pointerPredictor;

    private List<Point> _actualPoints = new List<Point>();
    private List<Point> _predictedPoints = new List<Point>();

    private SwapChainPanel _panel;

    public PointerPredictionRenderer(SwapChainPanel panel)
    {
        _panel = panel;
        _panel.Loaded += SwapChainPanel_Loaded;
    }

    private void SwapChainPanel_Loaded(object sender, Microsoft.UI.Xaml.RoutedEventArgs e)
    {
        _queuecontroller = DispatcherQueueController.CreateOnDedicatedThread();
        _queuecontroller.DispatcherQueue.TryEnqueue(DispatcherQueuePriority.High,
            () =>
            {
                // Set up the pointer input source to receive pen input for the swap chain panel.
                _inputPointerSource = _panel.CreateCoreIndependentInputSource(InputPointerSourceDeviceKinds.Pen);
                _inputPointerSource.PointerPressed += InputPointerSource_PointerPressed;
                _inputPointerSource.PointerMoved += InputPointerSource_PointerMoved;
                _inputPointerSource.PointerReleased += InputPointerSource_PointerReleased;

                // Create the pointer predictor for the input pointer source. By default it will be configured
                // to predict points 15ms into the future
                _pointerPredictor = PointerPredictor.CreateForInputPointerSource(_inputPointerSource);
            });
    }

    ~PointerPredictionRenderer()
    {
        Dispose();
    }

    public void Dispose()
    {
        if (_pointerPredictor != null)
        {
            _pointerPredictor.Dispose();
            _pointerPredictor = null;
        }

        _inputPointerSource.PointerPressed -= InputPointerSource_PointerPressed;
        _inputPointerSource.PointerMoved -= InputPointerSource_PointerMoved;
        _inputPointerSource.PointerReleased -= InputPointerSource_PointerReleased;

        _inputPointerSource = null;
        _queuecontroller = null;
    }

    private void InputPointerSource_PointerPressed(InputPointerSource sender, PointerEventArgs args)
    {
        // Store the new point in contact.
        _actualPoints.Add(args.CurrentPoint.Position);
    }

    private void InputPointerSource_PointerMoved(InputPointerSource sender, PointerEventArgs args)
    {
        // Only render ink and query for predicted points when the pointer is in contact.
        // There are no predicted points if the pointer is not in contact.
        if (args.CurrentPoint.IsInContact)
        {
            // Store new points received in this event.
            var intermediatePoints = args.GetIntermediatePoints();
            foreach (var point in intermediatePoints)
            {
                _actualPoints.Add(point.Position);
            }

            // Query for the predicted points from the predictor.
            var predictedPoints = _pointerPredictor.GetPredictedPoints(args.CurrentPoint);
            if (predictedPoints != null)
            {
                foreach (var predictedPoint in predictedPoints)
                {
                    _predictedPoints.Add(predictedPoint.Position);
                }
            }

            // Render the new ink stroke and the predicted ink stroke.
            RenderInk();
        }
    }

    private void InputPointerSource_PointerReleased(InputPointerSource sender, PointerEventArgs args)
    {
        // Clear the stored ink points and erase the predicted ink rendered for this stroke.
        _actualPoints.Clear();
        ClearPredictedInk();
        _predictedPoints.Clear();
    }

    private void RenderInk()
    {
        // Render the ink strokes defined by _actualPoints and _predictedPoints.
        throw new NotImplementedException();
    }

    private void ClearPredictedInk()
    {
        // Clear the ink stroke defined by _predictedPoints.
        throw new NotImplementedException();
    }
}

備註

此物件通常用來減少筆跡輸入的轉譯延遲。 在某些情況下，當使用者快速繪製時，畫筆提示與轉譯的筆跡之間可能會有明顯的間距。

屬性

PredictionTime

取得或設定 PointerPredictor 物件應該嘗試預測指標輸入的目前時間到未來的距離。

方法

Close()	關閉 PointerPredictor 並釋放系統資源。
CreateForInputPointerSource(InputPointerSource)	為指定的InputPointerSource建立PointerPredictor的實例。
Dispose()	執行與釋放 (Free)、釋放 (Release) 或重設 Unmanaged 資源相關聯之應用程式定義的工作。
GetPredictedPoints(PointerPoint)	擷取指定 PointerPoint的預測點集合。